In San Antonio, a modeling study found that if traffic congestion were to increase by 25 percent, posting nearby railroad crossing closing delays on freeway dynamic message signs would reduce crashes by 8.7 percent.

October 2000
San Antonio,Texas,United States

Summary Information

This project deployed acoustic and Doppler radar sensors on railroad tracts to detect the presence, speed, and length of trains as they approached highway grade crossings. Sensor data was transmitted to the TransGuide Control Center where computer programs calculated and predicted the time and duration grade crossings at or near freeway exits would be blocked. This information was posted on freeway dynamic message signs to warn exiting drivers of possible delays.

The system was found to work well; however, at the time of the study low levels of congestion in the network did not warrant the implementation of an advanced warning system to avoid long delays. Simulation techniques were used to show the potential benefits of the system and to identify a decision-point at which congestion levels would warrant such a system in the future.


With a 20 percent driver compliance rate the crash rate would decrease by 8.7 percent.

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Advanced Warning for Railroad Delays in San Antonio, Lessons Learned from the Metropolitan Model Deployment Initiative

Author: Carter, Mark, et al.

Published By: Federal Highway Administration, U.S. DOT

Prepared by SAIC for the U.S. DOT

Source Date: October 2000

EDL Number: 13284



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Goal Areas


Typical Deployment Locations

Metropolitan Areas


railroad crossings, HRI, Highway Rail Intersections, grade crossing closure, railroad crossing, AWARD

Benefit ID: 2007-00444